It is possible to add more times in 1 single skill? for exemple 30 min / 1 h / 2 h/ etc etc?

Please explain further what's the goal here.
Skill duration when you press a skill to someone ( the time it lasts on him if its a curse ).

Skill duration as skill cooldown?

Skill duration as skill cast time?

<set name="abnormalTime" val="3600"/> this skill time (Buff time = how much durring one buff. That i want to say)

Well. If it is a simple skill,you can add different durations for each level.